Oil-soluble azo dye



Patented Jan. 1, 1935 I i I I oiisesomnmhzo'nyn RalphBl-Payne, Yhassignor to National A'fiiline&Chefinca1"(3oni1?aiiy;.Ind; New York,

"N.Y ,a'eoi poraitioniofiNewYork V p v .i-Nwhmmingv ..:Application.Dcember 21,1932; r

, Serial No. 648,217 a p I 14" claims." (oi-:- zsbes i This. invention relates to oii -s'oi-ubleaz'o :dy'esh vet-1t may be-initially'obt'ained, apart of the cor- Itrelates moreparticularly'to secondary-am dye; in'g ma t r Separates up n-sta d n stuffs soluble in benzeneand othernorg' anie -so1'- According to the p s nt 'iIiVi IitIOli HB-WZTdY vents and 'to com'position'scontaining the-same. stuffs are obtainable by up beta-naphthoi' 5 It hasheretofore beenpfficiposeel to men-mem with Jan aminoaz oxylene which is obtainable 6 rial by means" of a secondary :a'z'o' .res'iil-ti-ng fromoexylidineor a mixtureof xylidines containfromthe coupling of beta-naphtliol ih alkaline" ingalarge proportion'of o-x ylidene. 4 solution with a diaz'o-tized amincazexylenevob The invention accordingly comprises the. prodtainable'fron'ri atechnical xylidih; that is, a mix uctshaving the properties and characteristics,

10 ture of 'isomer'ic -a'minoxylehe compounds result= andlthe steps and theirrelationemployed.- in-the =10 ing-from the nitration reduction ofthe-xylene preparation of theproducts, all of which are exfraction ofcoaltar distillate eneranynavmg? amplified. inthe productsvand processes hereinaboi-ling point range of-about 13715" tol 40;5- Ctralter disclosed: The scopeof the -invention is'inwhich mixture generallycontains alarge pr'operdicated intheappended'patent claims tion ofmeta arid/of para xylidine arid o' a Inflprepali'ng the dyestuffs of the-presentinfg lfi comparatively small proportion-o fortho xyli vention, in accordance with a preferred method, The resulting products, howev aw'le -the o ea of procedure, the alkali metal salt of beta-naphti'on that 'the'y' are not soluble 'i "(ehzri'e' a dthol is coupledih an alkaline coupling medium, other organic solvents to a satisfactory extent such as, aqueous-sodium carbonate solution, with sothat ordiriarily solutions of 'theidesi r-ed 'con a diazotizedi'aminoazoxylenof which not less 20' centration but free from insoluble matter than 50 per control? the xylyl radicals are derivanot be obtained, and,.. moreover, when concentives of o-xylene (for example, diazotized aminotrated solutions of the products are prepared azo-o-xylene itself, or a mixture of diazotized some of the 'protiluct settles olit uponstanding aminoazoxylenes ofwhichvnot lessithah :5'0eper One use for which thesaid' dyehas ld'ee'n p'rdl centlof the xylyl radicalsi'are derivatives essay-:25 posedis' in the coloring of gas'ol-i nei Gasoline leriei*tha;.t-.is; o-xylylradicals); J containing'l'ead tetraethyl" is"usually colored to; Theaminoazoxylenermay"he preparedlin ta-ny distinguish it from other gasol'iincs-flih" v-iew'oithe suitableimann'er: from Io-ixy'lidine .or 2; Suitable highly poisonouscharacter ofthc-leeld corhpouhd ymixture tof ,xylidiri'ese prepared l The coloring agent is prefer-ably added'tdth byf the-rrlethodmsually employed; for the prepara- 30 gasolineinthefoim ofaconceritrated"solhtion v tibrflofzother-"an'iinoazo:bodies of the benzenesea solvent which is readily miseibiewith-gamma; riesge for example, :bytreating 2.5: to 3-mo1s of the such as benzene. Inorder" s'atisfactorily to colo xylidine'with about 1 molrof sodium nitrite int the gasoline containing lead? tetra-ethyl dissoli're pre'sencerof: an: excess of hydrochloric acid at atherein, it is apparent that the oloring agei 't temperatureaofa about 20 to' about 35 C., rear-- 35- should be fast to' li'ght should-h uhafiected b ranging; theiresulting:diazoaminoxylene-toamino lead tetraet-hyl, sho'uldbe sembiem benzene-an azof-io-xyleneiby;maintaining the mixture, result other hydrocarbons and other suitable soli ehts ing from the diazotization andcombination'; atia (such as ethylene dibromide; etc?) -t'o' -a sumeie temperature of 20 to 30 C. for almost 24'hours 40 extent to form a satisfactory co entrated sol tionfrom which thecoltring agent-eeesnee reafrangementiistcomplete; separatingthe' 'resultrate out-arid which has high tinctorial- C6I0I=H1g ingz'aminoahowexylene inthe:formsofitheihydlio power, so that upon high dilutio'r1 =with*gasoline" chloride,;-and wasl-1ing' it :Jwith-r dilute hydrochloric the coloring agent will be-present in s'cil-iitidn acidxuntil free fronilxylidinai sufiiciefi-tquantitiesto imparta definiteg easilyvThezxylidine-remployedifor the preparation M1145 discernible color. thetaminoazo' -oexylene may be loe-xylidine; or it While: the product resultingfrom the coupling maybe a:mixt'ureof=xylidines containing amaior of beta-naphthol-Wlth diazotized aminoaz'oxylene proportion-cot o-xylidine' and a' niinoe proportion prepared from "the technicalxylidine is a redof metaeiwand/oripara-xylidine's; A1 mixture'of:

"and then at a temperature'of to C. until 40" 50 dyestufi of satisfactory fastness to light; 'it-id'oesv xylidines containingsin excess of per cent, and

not dissolve in oily solvents such asbenz'e'neito a l" particularly'irihexces's of .per cent of o-'-xylisufiicient extent to produce stable: solutionsscon-f dines, ;based on'theweightio'f the'mixed-xyl-idines, tainihg the desired"'c'oncentrationslof. .coloring islpreferably employed.v One form "of .xylidine matter. Although .in-tsome cases-concentrated found to becof .value; inthe preparation of the 55 solutionstoh.theiproduct in'nbcnzeneiorcothenzsole prioduct'siofethe present'zinvention comprises-an "5,

naphthols having in sulting filtratewith hydrochloric acid to percipi-,

tatepara-xylidine as the hydrochloride, andfile tering off the resulting precipitate'from 'the'remaining solution of o-xylidine hydrochlor ides (as described for example in Journal of the Chemical Society (London), vol. 'i'77",ip.;; 65 (1000) Another formpfo-xylidine found to. be of value for the preparation of the products of the present invention comprises an o-xylidine which is obtainable by the nitration and subse f quent reduction of a xylene ffraction ofi coaltarqs I bycoupling of the diazotized aminoazo-oxylene with the beta-naphthol takes place. Dur- 'ing the coupling an excess of sodium carbonate cent. boilswithin the range of=142;tol4;5.5; C-'.-;'r for example a coal tar distillate having the fol-.-

distillate having a boiling point range of about to about 145 C., and preferablya xylene fraction of coal tar distillate of which 95 'per lowing composition:

Percent i 82. 6

the production of xylidinefrom xyleney present invention are xylyl-azo-xylyl=azo-betathe free state the probable formula:

. (3H RN=N-R =iv azo-xylol-azo-beta-naphthols in which at least 50,

and preferably more than 70, per cent; of the xylyl radicals of the mixture are o-xylyl radicals. a

The following examples will serve to illustrate .I the invention, but it will be evidentto oneskilled in the art that the invention is not'limited there to, and that changes may vbe made inthe ma-. terials treated, proportions of ingredients, methv od of procedure, reaction conditions, order-0fsteps and other detailswithout departing from: the scope of the appendedfpatenticlaims. The Whlch n i mamly of mtlfo'o'xylenes Pogether I I v a with small amounts of other isomeric nitro parts are by weight;

' Example 1 with hydrochloric acid, and'the resulting fraction of o-xylidine hydrochlorides is converted to the' three hours), and after addition of iron is comcorresponding mixture of aminoazo-oexylenes by all as more particularly described above. 1 Thereaction :mass is then neutralized by addi- Part B.Beta'-naphthol parts) isdissolve parts of soda ash and 1500 parts of ice. Aminoazo-o-xylene hydrochloride (315 parts) produced in accordance with the process of Part A, is dissolved in dilute hydrochloric acid (360 parts of 20 B. hydrochloric acid and 1000 parts of water) and is diazotized, while maintaining the temperature at about 10 to 12 C. by theaddition of ice (about 500' parts); by adding thereto suflicient sodiun'i'nitrite'to completely dia'zotize it (about .80., parts of sodium nitrite dissolved in about -2'40parts of water).

When the diazotization is comnletaewater is added to dilute the diazo solution (to a weight of about 6000 parts) and the diluted diazo solution is slowly added "(over a'.periodj'of"about 1 hour) to the alkalin'e solution" of beta-naphthol while maintaining 'the, temperature at about 5 C., whereandrof beta-naphthol is maintained in the couplingmedium-at all times by the addition of one or bothjof said compounds-as and if required...

When ,thecoupling is complete the reaction mixuntilfree from alkali and chlorides. If desired the dyestufi maybe dried at 80 C. The resulting The nitration of the xylene and the subsequent: product the dry state bronzy brownish reduction of xylidine may be carried out in ac-' cordance with the usual practice in the art for' powder insoluble in water,soluble in concentrated sulfuric acid to give a bluish green solutionrwhich, .upon dilution withwater, turns red and precipitates to a greater or less extent, and soluble in benzeneto give a red solution.

As compared; with the product made from an aminoazoxylene mixture-containing only a small amount of o-xylyl radicals, such as is obtainable from the mixed or technical xylidine employed as initial material in this example, the product of ;.the, example is. more completely soluble in benzene. i

, Example 2 Part A. To well agitated, cooled, high boiling xylene (1000 parts of a xylene fraction ofa coal tardistillatehaving a boiling range of 142.5 to 145 C.,.and consisting mainly of o-xylene) there is added mixed nitrating acid (3300 parts of a mixed acid containing 1'7 per cent. nitric acid, 65 per cent. sulfuric acid, and 18 per cent. water) at such a rate that the temperature of the reaction mixture does not rise above 15 C. The mixture is agitated with cooling until the nitration is completed, the resulting mass is allowed to stratify, andthe spent acid is drawn ofl from the upper oily layer containingthe nitro xylene. The oil,

5 xylenes, is then washed with dilute sodium car- ,u bonate solution and finally with water.

Part A.- A,technical xylidine, consisting main-' 5 ly of a mixtureof metaand paraexylidines and'iv containing a minor proportion of o-xylidin'e's, is treated to recover the o-xylidines as a separate fraction in the form of the hydrochlorides by treatment 'with acetic acid followed by treatment .;l= zrt Bi -A mixture of water (100 parts) hydro- 'chloric acid (117 parts of 20 B. acid), and nitroo-xylene resulting from the process of Part A (720 parts) isheated and refluxed with agitation in a jacketed iron kettle provided with suitable agitating means and a reflux condenser. Ground. iron (967(parts) is gradually added to the-agitated. mixture (over aperiod of two to pleted, live steam is passed into the reaction mass to continue the refluxing (for about 2.5 hours).

tion'of hydrated lime, and the resulting xylidine product. is recovered by distillation from the reaction massby indirect heat with the aid of a product (which consists mainly of a mixture of o-xylidines) is a reddish-brown liquid, of which 90 to 95 per cent. boils within a range of 219 to 244 C. at atmospheric pressure.

Part C.--To an agitated solution of an oxylidine product resulting from the process of Part B (132 parts of the reddish-brown liquid) in hydrochloric acid (43.8 parts, sp. gr. 1.18) there is slowly added a solution of sodium nitrite (28.8 parts) in Water (60 parts) while maintaining the temperature within the range 209-35" C. After the nitrite is all added, the reaction mixture is maintained at about to about C. for about fifteen hours; it is then heated to about 60 C. and maintained at said temperature for a further period of about three hours. Upon completion of the reaction, the reaction mixture is cooled to about 45 C. and hydrochloric acid (315 parts, sp. gr. 1.10) is slowly added. After stirring for about one hour, the reaction mass is added to water (80 parts), the mixture is agitated to complete precipitation (ten to fifteen hours) and the resulting aminoazoxylene hydrochloride mixture is filtered ofi and washed with dilute hydrochloric acid, to remove any unreacted xylidine. The resulting filter cake, which consists mainly of hydrochlorides of a mixture of isomeric aminoazoxylenes of which the xylyl radicals are mainly derivatives of o-xylene, may be employed in the subsequent operations in the form of a paste, or it may be dried under vacuum at about 50 C.

Part D.The aminoazoxylene hydrochloride resulting from the process of Part C is coupled with beta-naphthol in accordance with the process of Example 1, Part B. The resulting dyestufi is similar in properties to the dyestufi of Ex-, ample 1, Part B. I

As has been pointed out, the invention is not limited to the details of the above specific examples but various changes may be made, as will be evident to one skilled in the art. Furthermore, while the dyestufis of the present invention are of particular value in the coloring of gasoline containing lead tetraethyl, they are not limited in their application to such use, and in view of their solubility in organic solvents, they may be employed to color oil varnishes, wood stains, resinous compositions, cellulose and other lacquers, etc.

I claim:

1. The process of making an azo dye soluble in oil which comprises diazotizing an aminoazoxylene of which not less than 50. per cent. of the xylyl radicals are derivatives of o-xylene, and coupling the resulting diazo compound with betanaphthol.

2. The process of making an azo dye soluble in oil which comprises diazotizing a mixture of aminoazoxylenes of which not less than 50 per cent. of the xylyl radicals are derivatives of oxylene, and coupling the resulting diazotized product with beta-naphthol in an aqueous alkaline solution.

3. The process of making an azo dye soluble in oil which comprises coupling beta-naphthol in an aqueous alkaline solution with a diazotized aminoazoxylene mixture, resulting from the diazotization, combination, and rearrangement of a xylidine mixture containing not less than 50 per cent. of o-xylyl derivatives based upon the weight of the mixed xylidines.

4. The process of making an azo dye soluble in oil which comprises coupling beta-naphthol in an aqueous alkaline solution with a diazotized aminoazoxylene mixture, resulting from the diazotization, combination, and rearrangement of a xylidine mixture containing in excess of 70 per cent. of o-xylyl derivatives based upon the weight of the mixed xylidines.

5. The process of making an azo dye soluble in oil which comprises coupling beta-naphthol in an aqueous alkaline solution with a diazotized aminoazoxylene mixture, resulting from the diazotization, combination, and rearrangement of a xylidine mixture'containing in excess of 90 per cent. of o-xylyl derivatives based upon the weight of the mixed xylidines.

6. The process of making an azo dye soluble in oil which comprises nitrating a xylene fraction of coal tar distillate which boils within the range of about 140 to about 145.5 C., reducing the resulting nitro-xylene mixture to a mixture of xylidines, converting the resulting xylidine mixture to a mixture of aminoazoxylenes, diazotizing the aminoazoxylene mixture, and coupling the resulting diazotized product with betanaphthol in aqueous alkaline solution.

7. The process of making an azo dye soluble in oil which comprises nitrating a fraction of coal tar distillate which consists mainly of xylenes of which more than 90 per cent. is o-xylene, reducing the resulting nitro-xylene mixture to a mixture of xylidines, converting the resulting xylidine mixture to a mixture of aminoazoxylenes, diazotizing the amino-azoxylene mixture, and coupling the resulting diazotized product with beta-naphthol in aqueous sodium carbonate solution.

8. The process of making an azo dye soluble in oil which consists in diazotizing aminoazo-oxylene and coupling the resulting compound with beta-naphthol.

9. A colored composition of matter comprising xylyl-azo xylyl-azo-beta-naphthol of which at least 50 per cent. of the xylyl radicals are derivatives of o-xylene.

10. A colored composition of matter comprising a mixture of isomeric xylyl-azo-xylyl-azobeta-naphthols of which at least 50 per cent. of the xylyl radicals are derivatives of o-xylene.

.11. A colored composition of matter comprising a mixture of isomeric xylyl-azo-xylyl-azobeta-naphthols of which at least 70 per cent. of the xylyl radicals arederivatives of o-xylene.

12. A colored composition of mattercomprising a mixture of isomeric xylyl-azo-xylyl-azobeta-naphthols of which more than 90 per cent. of the xylyl radicals are derivatives of o-xylene.

13. A composition of matter obtainable by the process of claim 6 and comprising a mixture of isomeric xylyl-azo-xylyl-azo-beta-naphthols, being in the dry state a bronzy, brownish powder insoluble in water, soluble in concentrated sulfuric acid to give a bluish green solution, and soluble in benzene to give a red solution.

14. Xylyl azo xylyl azo beta naphthol in which the xylyl radicals are derivatives of oxylene.

RALPH B. PAYNE. 

